Jeremy Hobson: Now to New Mexico, where the state's largest wildfire ever is still growing, which means the cost of putting it out is growing as well. Last year, the Forest Service spent $1.4 billion fighting fires, and this year the bill could be even higher.

As Laurel Morales reports from KJZZ in Flagstaff.

Laurel Morales: Forest ecologist Wally Covington says for a long time, fire was seen as the enemy. And that allowed forests to grow thick.

Wally Covington: You can’t buy enough fire equipment, you can’t hire enough firefighters when you have the landscape so loaded with fuel as we’ve got it today.

Fire managers think about things like air pollution, water supply and saving homes when calculating the risks of fighting a blaze.

Tom Harbour is the Forest Service Director. He says there’s an art and science to making these tough decisions.

Tom Harbour: Sometimes the accumulation of those decisions will run into tens of millions of dollars.

And sometimes it costs next to nothing to monitor a fire in the remote wilderness.

But more and more people are moving to the woods. So often times, fire managers draw a map, and on one side they suppress a blaze where there’s a community nearby. And on the other side, they may let it burn into a rocky ridge where it puts itself out.